This invention relates to apparatus for handling flat, flexible web products and more particularly, to such items as plastic food bags.
In the past, such products have been presented to the consumer either in roll form from which the bags are detached along lines of transverse perforation or having a predetermined number in a carton. The instant invention relates to the latter category. A prior machine for boxing bags is co-owned U.S. Pat. No. 3,640,050. The instant invention finds advantageous use for similar products.
The instant invention, like the '050 patent, handles a stream of bags but differs significantly in the apparatus for the handling and ultimate boxing or cartoning. A significant feature of the invention resides in the apparatus for sequential handling of the bags involving gripping means.
Although the gripping means per se are known (see co-owned U.S. Pat. No. 3,599,805) there has been no teaching of utilizing a pair of gripping means operating in tandem. According to the invention, the gripping means first in the path of the stream of web products sequentially grips these products and assembles them into a stack--containing a predetermined number.
Thereafter, the first gripping means is deactivated and the web products continue in the path to a second gripping means which assembles another stack while the machine elements associated with the first gripping means are completing the folding and cartoning of the first developed stack. This arrangement makes possible significantly greater speed of operation while still maintaining positive control over the flexible web products, i.e., the bags.
More particularly, the deactivation of the first gripping means is accomplished by a unique "phasing" of the gripper actuating cam which facilitates the advantageous high speed operation. The deactivation of the gripping means can also be applied to the second gripping means, thereby achieving a "cull" mode of operation which is used on occasion to reject sub-quality bags or during adjusting/maintenance periods of operation.
Other objects and advantages of the invention may be seen in the details of the ensuing specification.